Diagnostic utility of endobronchial ultrasound elastography for detecting benign and malignant lymph nodes: a retrospective study.

Background: The endobronchial ultrasound (EBUS) elastography is a diagnostic tool used for measuring the elasticity of intrathoracic lesions. It is still essential for discussions about how accurate elastography is at identifying benign and malignant mediastinal and hilar lymph nodes. The objective of this study was to investigate the diagnostic utility of EBUS elastography and to determine the variables affecting this procedure. Methods: We conducted a single-center, retrospective study involving patients with suspected lung cancer who underwent EBUS elastography followed by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) at Zhejiang Cancer Hospital between October 2021 and March 2023. The pathological results of EBUS-TBNA, validated through a six-month follow-up, served as the gold standard. Each lymph node had its ultrasonic elastography indices recorded, including the elastography grading score, blue color ratio (BCR), blue color score, and short axis diameter. The diagnostic efficacy of elastography was assessed using the receiver operating characteristic (ROC) curve, which differentiated between benign and malignant lymph nodes. To investigate the factors impacting the elastography indices, multivariate logistic regression was used with multiple serological markers, lymph node location, and pathology. Results: Of the 168 patients, 322 lymph nodes were punctured, with 175 (54.3%) being malignant. The area under the ROC curve (AUC) for the combined index of elastography grading score and short-axis diameter was 0.702 [95% confidence interval (CI): 0.645-0.759]. While the pathology of the lymph nodes was found to influence the BCR, BCR was unable to distinguish between lymph nodes with benign conditions and those with small cell carcinoma. Conclusions: The use of elastography data alone may be inadequate for diagnosing metastatic lymph nodes. However, elastography can provide supplementary diagnostic information during EBUS-TBNA. Invasive EBUS-TBNA remains recommended as it aids in the identification of malignant lymph nodes when used in conjunction with pathological, radiological, and clinical findings.